I finally ran a spreadsheet on my cross country fuel mileage. Here are the stats running a 15" MadStad all the way down over the entire trip. Mirror hand wings were open most of the time. Most of the ride was highway miles with the throttle lock on. Ran regular 87 octane.
Min: 29.5 MPG - Strong sustained headwinds
Ave: 36.2 MPG
Med: 37.6 MPG
Max: 45.4 MPG
Max theoretical range for 6.6 gallons varied between [194 and 299] miles